Are Lactobacillus salivarius G60 and inulin more efficacious to treat patients with oral halitosis and tongue coating than the probiotic alone and placebo? A randomized clinical trial

Halitosis: etiology, prevention, and the role of microbiota

OBJECTIVES

This study aims to review halitosis research, discuss its various causes, and propose effective interventions based on the underlying etiologies and mechanisms. The main research question is to identify the primary factors contributing to halitosis and appropriate strategies to address them.

MATERIALS AND METHODS

A comprehensive literature review was conducted on halitosis and its associated causes, including oral pathological factors, oral microbial influences, microbial metabolic pathways, gastrointestinal diseases, and gut microbiota dysbiosis.

RESULTS

Unhealthy eating habits and an imbalance of microorganisms in the oral cavity and gastrointestinal tract were identified as primary causes of halitosis. Dental caries, periodontal disease, xerostomia, and digestive disorders like gastritis and irritable bowel syndrome were also found to be related to the development of halitosis. Due to poor oral hygiene or antibiotic use, disruption of microbial communities can result in dysbiosis, inflammation, and halitosis.

CONCLUSIONS

Halitosis is a multifactorial condition with various underlying causes, including oral and systemic diseases. Effective interventions should be tailored based on the specific etiologies and mechanisms involved.

CLINICAL RELEVANCE

Understanding the factors contributing to halitosis is crucial for developing appropriate treatment strategies. Enhancing oral hygiene habits, using antimicrobial drugs, or administering probiotics may help regulate oral or intestinal flora, thereby improving halitosis and overall oral health.

ORGANOLEPTIC AND HALITOMETRIC ASSESSMENTS DO NOT CORRELATE WELL IN INTRA-ORAL HALITOSIS: A SYSTEMATIC REVIEW AND META-ANALYSIS

BACKGROUND

The gold standard method for diagnosing oral halitosis is the subjective organoleptic measurement. Device-supported methods are also widespread worldwide. The challenges and safety concerns around performing organoleptic measurements during pandemics and the diversity of measuring device alternatives raised our clinical question: which halitometer is the most suitable for diagnosing halitosis?

METHODS

This systematic review was registered in PROSPERO (ID CRD42022320024). The search was performed on March 23, 2022 in the following electronic databases: MEDLINE, Embase, Scopus, Web of Science, and CENTRAL. Adult populations with or without halitosis were included, and patients with systemic diseases were excluded. Organoleptic (subjective) measurement and the device-supported (objective) methods were compared; the primary outcome was the correlation coefficient, and the secondary was the specificity and sensitivity of the devices. QUADAS-2 and QUADAS-C were used to evaluate the risk of bias in the studies. Random-effects meta analyses were performed on the outcomes, and the secondary outcomes were plotted on a common ROC plot.

RESULTS

A total of 1231 records were found in the 5 databases. After the selection process, 76 articles were eligible for the systematic review, and 14,635 patients were involved in the qualitative analysis. The pooled Spearman's correlation coefficient (c.c.) for sulfide monitors was 0.65; 95% CIs: [0.53-0.74]; I2 = 95%, P < .01. The pooled Spearman's c.c. for portable gas chromatographs was 0.69; 95% CIs: [0.63-0.74]; I2 = 12%, P < .01. The pooled Spearman's c.c. for gas chromatographs was 0.76; 95% CIs: [0.67-0.83]; I2 = 0%, P < .01.

DISCUSSION

None of the most commonly used halitometers proved to be significantly superior to the others. Halimeter and OralChroma measurements did not correlate well with the organoleptic level of oral halitosis in adults. Therefore, better halitometers need to be developed as an alternative to organoleptic measurements.

How Do Prebiotics Affect Human Intestinal Bacteria?-Assessment of Bacterial Growth with Inulin and XOS In Vitro

Prebiotics are believed to exhibit high specificity in stimulating the growth or activity of a limited number of commensal microorganisms, thereby conferring health benefits to the host. However, the mechanism of action of prebiotics depends on multiple factors, including the composition of an individual's gut microbiota, and is therefore difficult to predict. It is known that different bacteria can utilize inulin and xylooligosaccharides (XOS), but an overview of which bacteria in the human gut may be affected is lacking. Detailed knowledge of how bacterial growth is affected by prebiotics is furthermore useful for the development of new synbiotics, which combine a living microorganism with a selective substrate to confer a health benefit to the host. Hence, we developed a statistical model to compare growth in vitro among typical human gut bacteria from different phylogenetic lineages. Based on continuous observation of the optical density (OD600), we compare maximal growth rates (rmax), maximal attained OD600 (ODmax), and area under the growth curve (AUC) of bacteria grown on inulin or XOS. The consideration of these three parameters suggests strain-specific preferences for inulin or XOS and reveals previously unknown preferences such as Streptococcus salivarius growth on XOS.

Lactobacillus paracasei ET-22 and derived postbiotics reduce halitosis and modulate oral microbiome dysregulation - a randomized, double-blind placebo-controlled clinical trial

Oral microbial dysbiosis is the primary etiologic factor for halitosis and may be the critical preventive target for halitosis. This study included randomized controlled trials (RCTs) assessing the effects of Lactobacillus paracasei ET-22 live and heat-killed bacteria on halitosis and the related oral microbiome. 68 halitosis subjects were divided into placebo, ET-22 live (ET-22.L) and ET-22 heat-killed (ET-22.HK) groups. Subjects took different lozenges three times a day for 4 weeks and underwent saliva collection and assessment of breath volatile sulfur compound (VSC) levels at the beginning and end of the intervention. Salivary volatile organic compounds were measured using HS-SPME-GC/MS, and the microbiome profile was determined by 16S rRNA gene amplicon sequencing. A positive decrease in breath volatile sulfur compound (VSC) levels was observed in the means of both ET-22.L and ET-22.HK groups after 4 weeks of intervention, being more marked in the ET-22.L group (p = 0.0148). Moreover, ET-22.L and ET-22.HK intervention remarkably changed the composition of total salivary volatile organic compounds (VOCs) and aroma-active VOCs. Key undesirable VOCs, such as indole, pyridine, nonanoic acid, benzothiazole, and valeric acid, were significantly reduced. Meanwhile, ET-22.L or ET-22.HK also altered the taxonomic composition of the salivary microbiome. The halitosis pathogens Rothia and Streptococcus were significantly reduced in the ET-22.HK group and the pathogenic Solobacterium and Peptostreptococcus were significantly inhibited in the ET-22.L group. Collectively, our study suggests that both ET-22.L and ET-22.HK can significantly inhibit the production of undesirable odor compounds in subjects with halitosis, which may be related to the changes of the oral microbiome.

Comparative Evaluation of the Inhibitory Effect of Lactobacillus rhamnosus on Halitosis-Causing Bacteria: An Invitro Microbiological Study

AIM

 To determine the effectiveness of Lactobacillus rhamnosus in inhibiting halitosis-causing bacteria relative to other possible inhibitors, such as mouthwashes.

MATERIALS AND METHODS

 This in vitro study was done using a diffusion test with three groups with 11 samples in each group: group A, Porphyromonas gingivalis; group B, Tannerella forsythia; and group C, Prevotella intermedia. At 24, 48, and 72 hours, the inhibitory effect of L. rhamnosus was tested.

RESULTS

A statistically significant difference was seen for halo formation in group A, where all 11 samples showed an inhibitory effect after 72 hours. After 48 hours, seven of the 11 samples in group B and nine of the 11 samples in group C showed inhibitory effects.

CONCLUSION

 The study found that L. rhamnosus had an inhibitory effect on halitosis-causing bacteria like P. gingivalis after 72 hours, which was statistically significant. The same was true for T. forsythia and P. intermedia after 48 hours. This means that L. rhamnosus has an inhibitory effect on halitosis-causing bacteria like P. gingivalis.

Influence of Lactobacillus reuteri, Bifidobacterium animalis subsp. lactis, and prebiotic inulin on dysbiotic dental biofilm composition ex vivo

BACKGROUND

Probiotic bacterial supplementation has shown promising results in the treatment of periodontitis and the maintenance of periodontal health. The purpose of this investigation was to evaluate the influence of Lactobacillus reuteri or Bifidobacterium animalis subsp. lactis supplementation with and without prebiotic inulin on biofilm composition using an ex vivo biofilm model.

METHODS

Subgingival plaque specimens from three periodontitis-affected human donors were used to grow biofilms on hydroxyapatite disks in media supplemented with varying combinations of prebiotic inulin, Lactobacillus reuteri, and Bifidobacterium animalis subsp. lactis. Relative abundances of bacterial genera present in mature biofilms were evaluated using 16S rRNA next-generation sequencing. Diversity metrics of microbial communities were evaluated using a next-generation microbiome bioinformatics platform.

RESULTS

Inulin supplementation produced statistically significant dose-dependent increases in relative abundances of Lactobacillus and Bifidobacterium species (p < 0.001) with concomitant decreases in relative abundances of Streptococcus, Veillonella, Fusobacterium, Parvimonas, and Prevotella species (p < 0.001). Inoculation with L. reuteri or B. animalis subsp. lactis increased the relative abundance of only the supplemented probiotic genera (p < 0.05). Supplemental inulin led to a statistically significant decrease in biofilm alpha diversity (p < 0.001).

CONCLUSIONS

The described ex vivo model appears suitable for investigating the effects of probiotic bacteria, prebiotic oligosaccharides, and combinations thereof on biofilm composition and complexity. Within the limitations imposed by this model, results from the present study underscore the potential for prebiotic inulin to modify biofilm composition favorably. Additional research further elucidating biologic rationale and controlled clinical research defining therapeutic benefits is warranted.

Efficacy of probiotics in the management of halitosis: a systematic review and meta-analysis

BACKGROUND

Halitosis is defined as a foul odour emitted from the oral cavity. Many interventions have been used to control halitosis from mouthwashes to chewing gums. Probiotics have been reported as an alternative method to alleviate halitosis.

OBJECTIVE

The present study aimed to investigate the effect of probiotics on halitosis from a time perspective.

DESIGN AND METHODS

This is a meta-analysis study performed in indexed databases up to February 2021. Randomised controlled trials that compared the effects of probiotics and placebo on primary outcomes (organoleptic (OLP) scores and volatile sulfur compound (VSC) levels) and secondary outcomes (tongue coating scores (TCS) and plaque index (PI)) were included. Data extraction and quality assessment were conducted independently by two reviewers. Publication bias and leave-one-out analyses were performed.

RESULTS

The standardised mean difference (SMD) and 95% CI were calculated to synthesise data. The data were subgrouped and analysed in the short term (≤4 weeks) and long term (>4 weeks) based on the follow-up time. Seven articles were included in this meta-analysis. The primary outcomes, OLP scores (SMD=-0.58; 95% CI -0.87 to -0.30, p<0.0001) and VSC levels (SMD=-0.26; 95% CI -0.51 to -0.01, p=0.04), both decreased significantly in the probiotics group compared with the placebo group in the short term. However, a significant reduction was observed only in OLP scores (SMD=-0.45; 95% CI -0.85 to -0.04, p=0.03) in the long term. No significant differences were observed in secondary outcomes. There was no evidence of publication bias. The leave-one-out analysis confirmed that the pooled estimate was stable.

CONCLUSIONS

According to the results of this work, it seems that probiotics (eg, Lactobacillus salivarius, Lactobacillus reuteri, Streptococcus salivarius and Weissella cibaria) may relieve halitosis in the short term (≤4 weeks). The results of the biased assessment, limited data and heterogeneity of the clinical trials included might reduce the reliability of the conclusions.

The efficacy of probiotics in the management of intra-oral halitosis: a systematic review

OBJECTIVES

To evaluate the efficacy of probiotics in reducing halitosis of dental origin.

METHODS

MEDLINE, EMBASE, and CENTRAL were searched up to and including June 2020. Randomised placebo-controlled, double-blinded clinical trials in systemically healthy adult patients who were given any form of probiotics to manage halitosis of dental origin were included. Primary outcome measures were organoleptic scores and volatile sulphur concentration levels. Secondary outcome measures were microbiologic parameters and quality of life (QOL).

RESULTS

Of the 301 potentially relevant articles, eight articles were selected for the review. The risk of bias assessment showed that two studies were of low risk of bias, four studies had some concerns, and two studies had a high risk of bias. The beneficial effect of probiotics could neither be confirmed in periodontally treated patients administered with up to 8 weeks of probiotics, nor in periodontitis patients who received both non-surgical periodontal therapy and adjunctive probiotics up to 90 days. Microbiological findings 1 month after probiotics administration and QOL measures showed no significant differences compared to control. Considerable heterogeneity was observed among probiotic administration protocols.

CONCLUSIONS

The available evidence suggests no convincing benefit for the use of probiotics in the management of halitosis. Standardised protocols on recruitment of halitosis subjects and organoleptic measurements are required for future studies on probiotics as an intervention.

CLINICAL RELEVANCE

The lack of well-conducted studies with a low risk of bias precludes any clinical recommendation. Further research is needed to verify the efficacy of probiotics in the management of intra-oral halitosis.

Pathophysiology and Management of Tongue Involvement in COVID-19 Patients

Evaluate the lingual manifestations of COVID-19, and provide a clinical guide in managing these symptoms. Electronic databases, such as PubMed/Medline, and Scopus were searched until November 1, 2020, and only randomized controlled trials, cross-sectional and cohort studies, as well as case reports and series, and review articles in English were considered. A total of 40 studies were included in this study. Lingual involvement has been extensively reported in patients with coronavirus disease 2019 (COVID-19). The most common features of lingual involvements were red or light red, yellow coating, and greasy coating tongue, though other complications, such as pale, purple, white coating, grayish-black coating, rough, tender, puffy, spotty, prickles, fissured, and tooth-marked tongue was also reported. Poor oral hygiene, opportunistic infections (OIs), medications, and hyper-inflammatory response to infection are the most common predisposing factors for the onset of oral lesions in patients with COVID-19. In conclusion, the current review described the lingual manifestations of COVID-19, and as oral complaints are relatively common in COVID-19 patients, an intraoral examination should be conducted in all suspected cases of SARS-CoV-2 infection.